Statement of the Problem
Ice causes problems on many various kinds of surfaces. For example, ice accumulation on aircraft wings endangers the plane and its passengers. Accumulations of ice formed by the condensation and freezing of water on the outside surfaces of heat exchangers in freezers reduces heat transfer efficiency and often results in physical damage to cooling coils. Problems associated with ice are particularly obvious with respect to land-based transportation systems, including automobiles, trailers, trolleys and railroads. Ice on automobile windshields and windows decreases driver visibility and safety. Removing ice from windshields is a recurring chore that is often unsatisfactorily performed. Ice on roads is frequently a cause of automobile accidents resulting in personal injury and death, as well as material damage. Ice on airport runways causes delays in air traffic. Large amounts of material resources, money and man-hours are spent annually to remove ice and snow from roads, sidewalks and bridges to reduce risks of slipping and skidding on iced surfaces.
Conventional resistive heating systems to remove ice and snow have high, sometimes economically unfeasible, power requirements. Application of chemical agents to remove ice has temporary effects, is limited to relatively small surface areas, and is labor and equipment intensive. Also, once ice has formed on surfaces, it may be difficult to remove. Also, some applications require the prevention of ice in the first place. Growth of even 1 mm of ice at certain locations on airplane wings and helicopter blades seriously decreases their performance. Other examples include ice growth on windshields of airplanes and automobiles and on the outside of freezer coils, which have a low level of tolerance to even thin layers of ice.